The use of a sod harvesting machine to cut slabs of sod from a sod field and then prepare the sod slabs for transport to a work site is known in the art. Once the sod slab is at the work site the sod slabs are laid down on top of the soil to enable the grass in the sod to take root in the soil. The use of sod handling machines is also known in the art. One way of handling the sod after the sod slab is cut from the field is to roll the sod slab into a cylindrical sod roll. One can then transport the sod to the work site where the sod is unrolled as the sod is laid down at the work site. Examples of sod handling apparatus are shown in our U.S. Pat. Nos. 6,783,318; 6,681,864; 6,364,027; and 6,296,063 which I hereby incorporated by reference.
Another way of handling a cut sod slab is to leave the sod slab in a flat or unrolled condition and pile the sod slabs on a pallet and then transfer the pallet with the sod slabs to a work site where the sod slabs are removed from a pallet and laid on the top soil.
Whether the sod slabs are rolled or left in a flat condition the sod slabs need to be transferred from one location to another location without destroying the integrity of the sod slabs.
One of the difficulties with handling sod slabs in an unrolled condition is that it is sometimes more difficult to transfer an unrolled or flat sod slab as opposed to a compact sod roll since the integrity of sod slab is affected by numerous factors including the type and amount of grass roots in the soil, the adherence of soil particles to each other and the adherence of the soil particles to the grass roots in the sod slab. In general care must be taken to ensure that integrity of the unrolled sod slab remains intact during the transport so that the sod slab can be laid down at the work site.
One method for lifting unrolled sod slabs uses a set of clamps that grasp the blades of grasses to transfer the sod slab in an unrolled condition. Such a device is shown in U.S. Patent application Publication U.S. 2005/0000704. In some cases it may be preferable to roll a sod slab into a cylindrical sod roll as the roll geometry increases the integrity of the sod for handling as well as allowing hooks or the like for piercing the sod roll to enable one to lift the sod roll. However, if the hooks are not properly applied to a roll of sod the sod roll can unwind or the sod can tear making it difficult to handle. Thus both methods of handling sod slabs either in a rolled condition or an unrolled condition are known in the art.
In contrast to the prior art devices and methods of moving sod the present invention includes a sod lift mechanism that enables one to lift and transport a sod slab from the sod field to the work site whether the sod slab is in a flat condition or in a rolled condition while maintaining the integrity of the sod slab. The various embodiments of the sod handling apparatus described herein include an apparatus for holding sod with a pressure differential across the sod slab, a sod transport mechanism; a sod carriage, a sod bed positioning system, a bump bed for lifting sod from a conveyor as well as use of such sod handling apparatus in sod machines such as sod harvesters. In addition the inventions include novel methods with one method including a method of machine stacking sod to maintain the integrity of a sod stack. The embodiments for transferring sod are shown and described with respect to a sod harvester although each of the various embodiments of the sod handling apparatus shown and described can be used in equipment other than sod harvesters.